Sildenafil citrate increases myocardial cGMP content in rat heart, decreases its hypertrophic response to isoproterenol and decreases myocardial leak of creatine kinase and troponin T

Table 1 The heart coefficient (mg/g body wt.), myocardial cGMP level (pmoles/g wet tissue), CK activity (U/mg tissue protein) and serum level of cTnT (ng/ml) in rats after 10 days of treatment with: vehicle (group I), isoproterenol (group II), sildenafil/ isoproterenol (group III), sildenafil (group IV) and sildenafil/isoproternol/ N^ω-nitro-L-arginine (group V).

	Heart coefficient	Myocardial cGMP	Myocardial CK	Serum cTnT
Group I n = 10	3.33 ± 0.18*	4.76 ± 1.03**	6.03 ± 0.35**	0.38 ± 0.13*
Group II n = 8	5.27 ± 0.17**	4.12 ± 1.36**	3.10 ± 0.35*	6.50 ± 1.29***
Group III n = 13	3.75 ± 0.48*	10.51 ± 3.05***	5.62 ± 0.44**	3.71 ± 1.16**
Group IV n = 15	3.49 ± 0.67*	10.14 ± 3.24***	5.80 ± 1.02**	0.75 ± 0.28*
Group V n = 8	5.31 ± 0.47**	1.80 ± 0.54*	3.47 ± 0.37*	6.34 ± 1.14***

NB: Isoproterenol was given at the dose of 5 mg/kg daily s.c. and sildenafil was given at the dose of 0.7 mg/kg daily i.p. and N^ω-nitro-L-arginine was added to drinking water at the concentration of 10 mg/L.
Values are mean ± SEM. n: number of rats survived for 10 days
One-way ANOVA test followed by Student-Newman-Keuls post-hoc test. Values forming homogeneous subsets are as follow: *homogeneous subset 1, ** homogeneous subset 2 and *** homogeneous subset 3. Significant difference existed between different subsets (P < 0.05)